Fuel injection systems for multicylinder engines



y June 30, 1959 H. sToLl. 2,892,453

FUEL INJECTIONSYSTEIMS FOR MULTICYLINDER ENGINES Filed Dec. 12, 1957 4 Sheets-She'et 2 wf/vm@ Manu? /44/ Filed Dec. l2, 1957 June 30, 1959 H. sToLL 2,892,453

FUEL. INJECTION SYSTEMS FOR MULTICYLINDER ENGINES 4 Sheets-Sheet 3 June 3o, 1959 H. STOLL w 2,892,453

" FUEL INJECTION SYSTEMS FOR MULTICYLINER ENGINES Filed Dec. l2, 1957 4 Sheets-Sheet 4 Nl 9m;

Ilma? www YUWW United States Patent O f ass-2,4532

INJEGTION SYSTEMS FOR MULTI ENGINES Hermann Stoll, Wuerttemberg, Germany, assiguorto Robertosch G-mtbHq Stuttgart, Germany Application December 12, 1957, SerialNo. 702,332.

Claims. priorityg, application Germany December 13, 1956` 7i Claims. (Cl. 12S- 139) The present invention relatesto internal; combustion engines.

More particularly, the-presentlinvention. relates to;` fuel supply` systems for multicylinder four-stroke internal combustionengines. The invention is patricularly-applilcable toengines= which have more thanthree cylinders, and theinvention is concerned with fuel-supply.systemswhere thefueliisinjected into-the engine.

One off theobjects` of thepresent invention is to provide a fuel injection system for a-multicylinder internal combustion engine where each of the: cylinders has its own ignition means, and* this fuel supply system has a far greater eiciency than previously known fuel supply systems.

It isA aparticular object ofi the present invention to providea fuelfsupply-system ofthe-above type which will enable an engine toprovide a higher output: at less cost than has hitherto been possible; y

It isA alsoan objectl of the present invention to provide structure capable of accomplishing all of' the above ob-r jects and at the same time composed-off simple and ruggedly' constructed elements which are very reliable in operation.

With the above objects inview, the present invention includes in as fuel'l supplysystem for va multicylinder fout-stroke internal combustion engine having an ignition meansin each of Tits-cylinders,` at least one injection pump means for;v intermittently pumping a charge offuel during operationofthe engine. A discharge conduit means leads: from the injection pump means andiV receives the fuel pumped thereby; A plurality ofv branch conduit means communicate with and branch from the discharge conduit means and respectively lead toward the cylinders of-ithe englfll'andaplurality o f injection valve means are respectively-connected tovand communicate withv the plurality of' branch conduit meansfor receiving the fuel pumpedthrough the latter. The plurality of injection valve, means automatically open whenpredeterminedpressures'are reached in theplurality of branch lconduit means, respectively; The engine includes a plurality of intake valves'forfthe engine cylinders, respectively, andan iny take manifold leads tothe engine cylinders, the intake' valves communicating With thesintake manifold. The pluralityofl injection valve means communicate with the interior offthe'intake manifold at locations respectively adjacent the intake valves. In accordancefwith the pres` entinvention a plurality of throttling means are respcc-v tivelylocatedi in theplurality of branch conduit means for respectivelyn providing in the plurality of branch conduitlmeanspressure dropsequal at least to 1.3 times the pressuresA at` which' the pluralityof injection valve means automatically bpem 'lihenovefeatures'whichf are considered as characteristicfora theinyentiouare set forthinfparticular. in the appended claims. Theinvention-itsel, however,A both as'J tos'itsf construction and its method ofoperation,- together withLw additional# objects"4 andl advantages thereof,

2,892,453 Patented., J une: 3,0,` 19,59

2v will be best understoodfrom the following. description of specific embodiments, when read in connection with the accompanying drawings, inwhichr Fig;` 1 isa fragmentaryy partly sectional, partly sche maticA illustration of one possible embodimentl o the present` invention;v

Fig. 2V shows the mannerxin` whichthe fuelfsupply` systemis, mountedon thefengine and illustratesfin particular theintake, manifold and the` conduits: communicating therewith;

Fig. 3: is a sectional planview onY Iaur enlarged, scale taken, along line 3 -3 of Fig. 1 in the direction ofthe arrows.J and. turnedV throughz 90 ;4

Eig', 4. is= a sectional view taken: along line` 4--4A of Eig-1 in-'the-directionothe arrows;

Fig; i isapartly,y sectional elevational viewon y an4 eneA largedtscale ofan injection valve-used'inthetfuelsystem of the present invention;

Fig, 6- isa,y fragmentary schematic illustration. ofy ane other embodiment of` an injection pumpmeans capableao being nsedfin the-fuel; supply: system of; the presenti-inl' ventiong' Fig. 7.' is.V a. partly.- sectional schematic illustration of a third embodiment of' the present invention;J

Fig. 81 shjows aY distributor` arrangement of Fig. 7 in :p1an:view; and

Fig. 9: diagrammatically' illustrates f the operation; of the engine with, respect to different crank angles; as well as the cyclesy of operation offthe different embodiments of,- the invention.

Referringenow totthe-drawings, and toFig. 1` in particu,- lar, the fuel supply system includes au injection pump means lwhich; in the embodimentV of1Fig.-,1 is composed of' ag single. injection pump; Thisinjection pump1 1 in. cludes inf its interior. a; pistonl which is reciprocated by aplunger- 2 which is; actedupon by a cam 3; which: is rotated; aboutitsaxis; The cam 3 has eight camming portions; 4 intheA example illustratedinFig. 1', andthe structureof Fig. 1 v is adapted-toghe usedwith an eight cylinderf four-stroke internal, combustion engineA where each of the; cylinders has its own ignition, means such as a; suitable', spark plug, for example. The: fuell is :sucked: intoy the injectiony pump 1 from a fuel supply tank 5 diagrammatically illustrated,` in Fig; l-, and a dis*- Charge-,condujt means 6" corrununicates with.y thee injection p umpl to:` receive the fuel discharged` thereby at' each cycle'off, operations; During a single rotation of4 thei-cam 3. the injection pump;1" will perform eight cyclesy of op# eration,y and; thus this!` injection pump: will: intermittently deliver a;charge'of:fuel to the dischargeconduit means -6s A plurality'off branch` conduit means 164 communicate with the single discharge conduit 6 of Fig.` l, and the connection between` the branch conduit means.V and:` the discharge conduit 6 isf provided by a ldistributor member 7. Asuitable nipple 8f interconnects the discharge conduit 6 with the; distributor 7, as isV shown most clearly in Figs. 1' and 4. The distributor 7 isprovided with a borei 9. leading from the nipple 8, as is shown most clearly in-,Fig. 4, and this bore 9 communicates with another bore 10`1-oftheidistributor member 7. Both ends of` the-bore 10 are closedtby. a pair ofvplug members 11 threadedly carried by the distributor'member 7, as shown in Figs. 3 and- 4; As is apparent from Fig. 3 the distributor memben 7.is provided with a` plurality of boresf14L branching fromfthebore 10; andthese bores 14 together withlthe nipples 15 with which they'` respectively communicate form partsfof! the plurality of branch conduitl means all of which communicate with the discharge conduit4 6. Thus; theseverall branch conduits`v 16 are-respectively connectedfby' the nipples 1S" withi thefbores 1:4105 the distributor member 7'; and-"these branch?y conduits 16 lead toward the several cylinders of the engine, respectively.

In accordance with the present invention a plurality of throttling means are respectively provided in the plurality of branch conduit means, and each of the throttling means takes the form of a pair of sealing rings 12 pressed 'between each nipple 15 and the bottom of the bore which receives the nipple 15. Between 4each pair of sealing rings 12 there is located a throttling disc 17 provided with a throttling aperture 18 located substantially centrally of the disc 17, as is shown in Fig. 3.

The several branch conduits 16 are respectively connected with injection valves 19, and these injection valves 19 are respectively connected to and communicate with the interior of the intake manifold 20 of the engine. The intake manifold 20 is fragmentarily illustrated in Fig. l, and the entire intake manifold 20 is shown in Fig. 2. The several cylinders of the engine 21 communicate with the several branches of the manifold shown in Fig. 2 through intake valves 24, respectively (Fig. 1), located in the inlets 23 of the several cylinders, respectively, which respectively communicate with the manifold 20. As is evident from Fig. 2 the branching portions of the intake manifold 20 lead from a centrally `elongated header portion which is provided at its ends with air lters 22. It will be noted particularly from Fig. 1 that the several injection valve means 19 communicate with the manifold 20 at locations which are respectively adjacent the intake valves 24 of the several cylinders. Thus, both Figs. l and 2 show the injection valve 19 located just ahead of the inlet valves of the several cylinders, respectively, and the several cylinders are indicated at I--VIII in Fig. 2. Thus, the injection valves 19 will spray fuel into the intake manifold just ahead of the intake valves of the several cylinders.

Referring now to Fig. 5, it will be seen that each of the injection valve means 19 includes a valve housing 19 which carries at the discharge end of the valve means an annular valve seat member 25 xed to the housing 19 by inwardly curving the bottom end of the housing 19', as shown in Fig. 5. A coil spring 26 bears at one end on the annular valve seat member 25, and the opposite end of the coil spring bears against a `washer 27 through which the valve stem 30 passes. The valve stem is provided adjacent its top end, as viewed in Fig. 5, with an annular groove which receives a ring member 28 which does not extend through a complete circle so that it can be slipped laterally into the groove, and as is apparent from Fig. 5 the ring member 28 is seated in a mating recess formed in the top face of the washer 27. At its bottom end the valve stem 30 is xedly connected with a hemispherical valve member 31 which bears against the conical valve seat provided by the valve member 25. The spring 26 urges the valve to closed position thereof shown in Fig. 5, and the valve is designed so that the pressures required to open and close the valve are substantially equal.

The cam 3 rotates at half the speed of rotation of the crank shaft o-f the engine, and during each rotation of the cam `3 the injection pump will pump eight charges of fuel at equal time intervals, and each of the charges will be equal in amount. These charges are delivered by the discharge conduit 6 to the distributor 7 from where the charges flow along the branch conduits 16 to the several injection valves 19. The size of the apertures 18 of the several throttling means'is so chosen that during the operation of the structure there is provided in each branch conduit a pressure drop at the throttling means which is at least equal to 1.3 times the pressure required to open the particular injection valve. Thereby it is achieved that at all working conditions of the engine each of the charges provided by the injection pump will be divided equally among the several branch conduits, so that each injection valve receives one-eighth of each charge. When the injection valves respectively receive the eighths of each charge they open and spray these fractional charges just ahead of the intake valves 24, respectively. It is preferred to have all of the injection valves require the same opening pressures so that all of the throttling means may have identical constructions. It has also proved to be advantageous to make the discharge conduit 6 between the pump 1 and the distributor 7 approximately twice as long as each of the branch conduits 16 extending between the distributor 7 and the injection valves 19.

The above-described operation of the above-described embodiment of the invention is shown graphically in Fig. 9 at b. Thus, during two rotations of the crank shaft While all of the cylinders of the engine move through a complete cycle of operations there will be equal delivery of fuel to all of the intake valves from all of the injection valves at each cycle of operation of the injection pump, and there are eight cycles of operation of the injection pump during one complete cycle of operation of the engine. The times during which the inlet valves of the several cylinders are open are indicated at a in Fig. 9. Although Fig. 9 shows that the injection takes place when the pistons of the several cylinders of the engine are at their top dead center positions, this timing is not essential and the injection may take place at any desired angular positions of the crank shaft of the engine.

The embodiment of the invention which is illustrated in Fig. 6 differs from that described above only in that the injection pump 35 of this second embodiment of the invention is driven by a cam carried by and driven by the cam shaft 36 and having only a single camming portion 37 to reciprocate the plunger which actuates the piston of the injection pump 35. In order to provide a high speed of movement of the piston of the injection pump during the pressure stroke of this piston the camming portion 37 is provided with a steep camming surface 38 shown in Fig. 6.

c As is apparent from portion c of Fig. 9, which illustrates the operation of the second embodiment shown in Fig. 6, the injection pump 35 moves through a single cycle of operations during the time that the crank shaft of the engine turns through two revolutions and the engine itself moves through one complete cycle of operations. The charge delivered by the injection pump 35 is distributed equally by the lbranch conduits to the several cylinders so that the single charge derived from the pump 35 is divided so that one-eighth of the charge reaches and passes through each injection valve 19. The structure connected to the discharge conduit 6 shown in Fig. 6 is identical with that connected to the discharge conduit 6 of Figs. l and 2. With this embodiment also the system may be timed so that the injection takes place at any desired angular position of the crank shaft of the engine.

In the third embodiment of the invention which is illustrated in Figs. 7 and 8 the injection pumpmeans is made up of a pair of injection pumps which are located within a single housing 40. The unillustrated pistons of the pair `of injection pumps are actuated by a pair of plungers 41 and 42, respectively, and these plungers 41 and 42 are in turn actuated by a pair of separate cams 43 and 44, respectively, fixed to and driven by the cam shaft 45. These cams 43 and 44 may be identical with the cam 37 of Fig. 6, and the cams 43 and 44 are displaced by with respect to each other.

The injection pump which `is controlled by the cam 43 delivers the fuel along the discharge conduit 47 to a nipple 48, and the injection pump controlled by the cam 44 delivers the fuel along the discharge conduit 49 to the nipple 50, so that in the embodiment'of Fig. 7 the discharge conduit means is made ofthe pair of discharge'conduits 47 and 49. The nipples 48 and'50 are respectively connected with 'and communicatev with a fbers `has four branches rather than eight branches. The pair ofldistributo'r members 51 and 52 are connected together in any suitable way and are displaced one with respect to the other by 90, as is evident particularly fromFig. 8. The numerals If-VIII of Fig. 8 illustrate the lmanner in whichnthe branch conduits 16 lead to the several cylinders. Thus, as may be seen from Fig. 8, the distributor member 52 distributes the fuel from the discharge V,condui`t/-l9 Vto the `branch conduits 16 which respectively lead to cylinders III-, VI, while the distribu- Vtin' v51 ldistributes the .fuel from the discharge conduit 47 to ,thebranch conduits 16 which respectively lead to the cylinders 11,] II, VII and VIII. The several branch `conduits 16 of Fig. 8 'are respectively connected with injector valve means 1`,9`f'as' described above, and this plurality of injector lvalfve means 1'9 are arranged in the manner descrihedabove ntconnection with Figs. 1

fand More'oveiylinech of theb'r'anch conduit means there isloca'ted .a throttling means as 'described above.

VThe manner which Jthe'enibodiment of Figs. 7 and 8 operates-is indicatedV at d in Fig. 9. The interval of operation between the pair of injector pumps is equal to 'the time required yfdr a single rotation of the crank shaft ofthe engine, and in this way-.the pair of injection pumps operate alternately "to provide charges at intervals equal to thetirn'e `required a single revolution of the crank shaft. The charges provided by the pair of injector `pumps are equal in amount, and each of the injector pumps supplies four of the cylinders.

I The entire charge of fuel provided to all of the cylinders of the engine during two rotations of the crank shaft thereof is equal in all three embodiments. In other words, Withthe embdiment of Fig. 6 the cylinders will receive justas much fuel as with the other embodiments because of the different size of the pump of Fig. 6 as compared that of Fig.` l, for example. Thus, there will be no differencein the amount of fuel supplied to the cylinders by the differentl embodiments described above.

All ofthe above-,described `embodiments have their own advantages. Thus, Ythe embodiment of Figs. l and 2 provides theV advantage of uniform distribution of the charge at each cycle of operation of the injector pump to all of the cylinders, sinceeach charge of the single injection `pump is equally divided among the several branch conduits.. The second vembodiment of the invention shown Fig. `6 and the operation of which is illustrated atc in Fig. lSi has the advantage of the greatest .possible simplicity'and Vthe lowest cost of construction. As for the third embodiment of `the invention whose operation is shovvn at d in Fig. y9, this embodiment presents the advantage .of'supplying 'the fuel from each in- *jectionl pump tonne-half of the cylinders during times `when these cylinders have their intake valves closed. Thus, ,by comparing portions aand d of Fig. 9 it will be ,seen that the charge delivered from one of the injection pumps takesplace when the `cylinders supplied thereby have their intakevalves closed. Thus, this embodiment of the invention VVprovides 'the advantage of guaranteeingthat'all of the fuel will Ifirst be delivered into the intake manifold and will not travel directly from the injection valves into the cylinders.

It will be understood :that each of the elements described above, or two or more together, may also iind a useful application in other types of internal combustion engines differing from the types described above.

While the invention has been illustrated and described as embodied in fuel supply systems for internal combustion engines, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a fuel supply system fo'r a multicylinder fours'troke internal combustion engine having an ignition means in each of its cylinders, in combination, at least one injection pump means for intermittently pumping a charge of fuel during operation of the engine; a discharge conduit leading from said injection pump means and receiving the fuel pumped thereby; a plurality of branch conduit means communicating with and branching from said discharge conduit and respectively leading toward the kcylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined pressures are reached in said plurality of branch conduit means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to the engine cylinders, said intake valves communicating with said manifold and said plurality of injection valve means communicating with the interior of said intake manifold at locations respectively adjacent said intake valves; and a plurality of throttling means respectively located in said plurality of branch conduit means for respectively providing in said plurality of branch conduit means pressure drops equal to at least 1.3 times said predetermined pressures at which said plurality of injection valve means automatically open.

2. In a fuel supply system for a multicylinder fourstro-ke internal combustion engine having an ignition means in each of its cylinders, in combination, a single injection pump for pumping a charge of fuel to all of the cylinders of the engine at each cycle of operation of said single injection pump; a discharge conduit leading from said injection pump and receiving the fuel pumped thereby; a plurality of branch conduit means communieating with and branching from said discharge conduit and respectively leading toward the cylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined pressures are reached in said plurality of branch conduit means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to the engine cylinders, said intake valves communicating with said manifold and said plurality of injection valve means communicating with the interior of said intake manifold at locations respectively adjacent said intake valves; and a plurality of throttling means respectively located in said pluralityv of branch conduit means for respectively providing in said plurality of branch conduit means pressure drops equal to at least 1.3 times said predetermined pressures at which said plurality of injection valve means automatically open.

3. In a fuel supply system for a rnulticylinder fourstroke internal combustion engine having an ignition means in each of its cylinders, in combination, a single injection pump pumping a single charge of fuel during one cycle of said injection pump which takes place during the time that all of the cylinders of the internal com bustion engine complete their respective cycles of operation; a discharge conduit leading from said injection pump and receiving the charge of fuel pumped thereby;

a plurality of branch conduit means communicating with and branching from said discharge conduit and respectively leading toward the cylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined pressures are reached in said plurality of branch conduit means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to the engine cylinders, said intake valves communicating with said manifold and said plurality of injection valve means communicating with the interior of said intake manifold at locations respectively adjacent said intake valves; and a plurality of throttling means respectively located in said plurality of branch conduit means for respectively providing in said plurality of branch conduit means pressure drops equal to at least 1.3 times said predetermined pressures at which said plurality of injectionvalve means automatically open.

4. In a fuel supply system for a multicylinder fourstroke internal combustion engine having an ignition means in each of its cylinders, in combination, injection pump means for intermittently pumping at least one charge of fuel during operation of the engine; discharge conduit means leading from said injection pump means and receiving the fuel pumped thereby; a plurality of branch conduit means communicating with and branching from said discharge conduit means and respectively leading toward the cylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined pressures are reached in said plurality of branch conduit means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to the engine cylinders, said intake valves communicating with said manifold and said plurality' of injection valve means communicating with the interior of said intake manifold at locations respectively adjacent said intake valves; and a plurality of throttling means respectively located in said plurality of branch conduit means for respectively providing in said plurality of branch conduit means pressure drops equal to at least 1.3 times said predetermined pressures at which said plurality of injection valve means automatically open.

5. In a fuel supply system as recited in claim 4, said injection pump means comprising a pair of injection pumps which alternately supply charges of fuel at equal time intervals, and said discharge conduit means including a pair of discharge conduits respectively leading from said pair of injection pumps to the plurality of branch conduit means, one half of the plurality of branch conduit means leading from one of said discharge conduits and the other half of said plurality of branch conduit means leading from the other of said discharge conduits, each of said injection pumps performing a single cycle of operations during the time that all of the cylinders of the engine move through a complete cycle of operations, and each of the injection pumps supplying fuel to one half of the number of cylinders of the engine during the time when the intake valves of the latter half of the cylinders are closed, so that a charge of fuel is never supplied to a cylinder during the time when its intake valve is open.

6. In a fuel supply system for a multicylinder fourstroke internal combustion engine having an ignition means in each of its cylinders, in combination, at least one injection pump means for intermittently pumping a charge of fuel during operation of the engine; a discharge conduit leading from said injection pump means and receiving the fuel vpumped thereby; a plurality of branch conduit means communicating with and branching from said discharge conduit and respectively leading toward the cylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined substantially equal pressures are reached in said plurality of branch conduit means, respectively, the pressures which are respectively required to close said plurality of injection valve means being substantially equal to the pressures required to open said plurality of injection valve means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to the engine cylinders, said intake valves communicating with said manifold and said plurality of injection valve means communicating with the interior of said intake manifold at locations respectively yadjacent said intake valves; and a plurality of throttling means respectively located in said plurality of branch conduit means for respectively providing in said plurality of branch conduit means pressure drops equal to at least 1.3 times said predetermined pressures at which said plurality of injection valve means automatically open.

7. In a fuel supply system for a multicylinder fourstroke internal combustion engine `having an ignition means in each of its cylinders, in combination, at least one injection pump means for intermittently pumping a charge of fuel during operation of the engine, said injection pump means including a reciprocating plunger which reciprocates a piston of the injection pump means and'a rotatable cam which acts on said plunger, said cam having a steep camming portion which moves said plunger at high speed during the pressure stroke of the piston of the injection pump means; a discharge conduit leading from said injection pump means and receiving the fuel pumped thereby; a plurality of branch conduit means communicating with and branching from said discharge conduit and respectively lea-ding toward the cylinders of the engine; a plurality of injection valve means respectively connected to and communicating with said plurality of branch conduit means for receiving the fuel pumped through the latter, said plurality of injection valve means automatically opening when predetermined pressures are reached in said plurality of branch conduit means, respectively; a plurality of intake valves for the engine cylinders, respectively; an intake manifold leading to theengine cylinders, said intake valves communicating with said manifold and said plurality of injection valve means communicating with the interior of said intake manifold at locations respectively adjacent said intake valves; and a plurality of throttling means respectively located in said plurality of branch conduit means for respectively providing in said plurality of branch conduit means pressure `drops equal to at least 1.3 times said predetermined pressures at which said plurality of injectionvalve means automatically open.

No references cited. 

